Posted
by
Soulskill
on Wednesday June 11, 2014 @07:12AM
from the would-go-great-on-michigan's-pockmarked-roads dept.

cartechboy writes: Remember back in the day when we all thought we'd be driving flying cars in the future? Well that clearly didn't happen, though it still might in the future. But somewhere inside Toyota there's a team of engineers who think hover cars might be a thing, and apparently there's a project underway at one of Toyota's "most advanced" research and development areas. We aren't talking Jetson's flying car, more like a car that merely hovers "a little bit away" from the road. Probably a few inches, with the aim to reduce road friction. With no wings or ridiculous speed, this is probably no simple process. No one really knows how long Toyota has been working on the idea, or how far along it is. Basically, don't expect flying Priuses any time soon...

Did anyone notice how dead-on accurate Google's automatic translation is on that site?
"D-Dalu is a completely new aircraft with a drive system based on four cyclo Giro rotors. Because of pairs of counter-rotating rotors drive the aircraft is permanently in a state of dynamic equilibrium with balanced centrifugal forces."
That's almost indistinguishable from a human translator.

Surely the underlying technology required is essentially what's already been developed for hovercraft, which already come in car sized variants. Don't get me wrong, I'm not saying it would be easy to stick a car body on them, develop intuitive controls and stick them on public roads; I'm just not sure the technology is as novel and underdeveloped as the summary makes out.

I'm not sure why a person would want a hovercraft for general use. It's way more efficient to just have car that rolls on wheels. Lifting the entire car off the ground with a cushion of air is terribly inefficient. Not that there aren't any uses at all, but as a general purpose vehicle on public roadways, it seems like a terrible idea.

Presumably the hover car would also have wheels. The benefit would come at motorway speed - an incredibly smooth ride with no road noise and, possibly, improved fuel economy. The off road potential of a hover car is also interesting.

Given 95% of resistance at motorway speeds is air resistance, not rolling resistance I'm not entirely sure how having a massive fan to create the lift and another to propel the car is going to improve fuel efficiency given how inefficient propellers are to start with.

Yes. A different matter entirely, as in, hovercars will never be useful in off-road applications. Unless, perhaps, they are antigravity vehicles and they are utterly unconcerned about slopes and grades. You cannot take a hovercraft up a grade of any note. Antique steam trains can ascend a steeper grade.

What about off-solid-ground applications, where they are already used? I have an actual use case in mind for a hover vehicle similar to a DUKW, where it could go into hovercraft mode over water that is too shallow to use conventional craft mode, but with a bottom too shallow to use the tires.

However, the on-road applications face another stumbling block: the laws in my US state (and likely most if not all of the others) require all vehicles used on public roads to be exclusively propelled by means of power

That's not true. It varies from vehicle to vehicle and between driving profiles, but it's usually 50-75% of the resistance at highway speed coming from aero drag - not 95%. Rolling drag remains a significant loss factor at all speeds.

That said, this doesn't sound to me like the most logical approach to tackle rolling drag - wheels are more efficient than hover as-is in most general-use cases, and I can easily envision a lot more that could be done. For example, you could use very high pressure (120+ psi) tires with a hard, thin central tread, relying on automatic camber to a thick, sticky side tread during accel, braking, cornering, or when traction control kicks in (the additional vibrational load from cruising on high PSI tires could be canceled with, for example, a cable vibration isolation system or active vibration cancellation). Such a system should be able to approach the rolling coefficients of hard steel wheels (a tenth that of traditional car pneumatic tires - effectively rendering rolling losses irrelevant). Heck, if you're going to that extent, it's not much further to go all the way to completely solid wheels (though you'd want foam-core carbon fiber or similar to keep the weight and in particular unsprung mass down, not solid steel) and not even have to deal with tire inflation or puncture risk. So long as you have a way to automatically shift to a thick, sticky tread as needed based on current traction conditions and have a mechanism to soak up the higher vibrational loads to maintain ride quality, you're fine.

Is that a pretty huge deviation from standard practice? Yeah, by no small amount, it's literally reinventing the wheel. But you know what, it's also a pretty huge deviation to have cars outright hover on the highway.;)

But yeah, you're right in that rolling losses aren't the *primary* loss mechanism on the highway. A lot more has to be done to tackle aero drag, and that's trickier - not least of which because the optimal shape varies based on speed and things like crosswinds (and the more you optimize your shape, the bigger of an issue this becomes). One of the more clever ideas I've seen - I don't know how it'd play out in the real world, mind you - was Aptera's plan to take a page from Gerald Bull's playbook and fill in the low pressure wake with air ducted in through the cabin. There's also a fair bit of research designed for aircraft (where aero drag is an even bigger issue) that could translate to cars, for example, skin textures or microstructures designed to maintain laminar flow or reduce surface drag. One of the more exotic variants of that which I've seen is a taut film outer-layer over a microscopic layer. The film vibrates in the wind between its ridges, setting up standing waves which separate the laminar flow from the surface, reducing the flow speed in contact with the surface and thus reducing direct surface drag. There've been peer-reviewed papers on it, and one of the researchers founded a company that now makes kits to reskin a variety of small aircraft (not very many thusfar, the skin has to be custom designed for each model). That's of course just one example among many, it's a very active field of research, as even a fraction of a percent reduced aero drag on a commercial airplane results in massive fuel savings.

Honestly, I'll be happy if we can just get people's style preferences to shift away from naturally high-drag forms like those ridiculous oversized front-end things where you can barely see over the hood. I know I'm out of the mainstream, but I love the look of aerodyamics. Real aerodynamics, not counterproductive curvy features that a lot of people think are "aerodynamic" but actually raise your drag. I want my car to look like a wingless plane, a car that cuts through the air like a knife rather than a clobbering oaf shoving it all around as it drives by ("Excuse me air, coming through, excuse me, sorry there!"). I want a rounded front end and a rear end that tapers vertically down with as long of a t

First off, in general to get up to 95%, you're talking "racing supercars" territory. But honestly, not even that (see below).

Secondly, the aero and rolling drag equations (in particular, rolling) are just approximations, along the lines of "assume a spherical cow". The real-world deviation from the formulas is usually described as changing drag coefficients under different conditions, but in the case of rolling drag, it changes so much at high speeds due to increasing magnitude standing waves on the

The tire idea is interesting, but I would think it would be easier to auto adjust the pressure so that the tire was either riding on the hard rubber strip in the middle (high pressure), or riding on the softer rubber on the rest of the tire (lower pressure). It seems like a better system than adjusting camber angles.

It could be (though that would have engineering challenges of its own, and not just noise minimization), but remember that compressing air is a rather lossy process. If you're rapidly dropping the pressure, say from 120psi to 20psi then back, every time you need traction, you're going to lose an awful lot of energy doing so.

Given that increased camber is often a good thing when cornering, and that there's no inherent physical loss mechanism in changing camber, and your required hardware to do so isn't parti

You are assuming the worst possible implementation for anything that doesn't directly agree with you, and the best possible implementation for things that agree with you. It's a form of confirmation bias, and it makes for an unfair evaluation of the ideas of others.

No, it simply is lossy, period. Air compressors are geneally at 10-20% efficienct, usually under 15% for small one. To get any sort of significant improvement on that you have to add in one or more bulky waste heat recovery cycles (yes, thermal engines), which are limited by Carnot's law, which dramatically limits your recovery potential.

It's not "confirmation bias", it's a fact; air compression is a highly lossy process. If you don't believe me, ask anyone else who has experience with compressors. Or just [google.is]

Honestly, I'll be happy if we can just get people's style preferences to shift away from naturally high-drag forms like those ridiculous oversized front-end things where you can barely see over the hood.

Part of the reason cars still look like this is for crash protection. Even mid-engine cars like Ferraris, as well as Teslas which have the motor in the back and batteries on the bottom, have long hoods, for crash protection. If you stick the passengers at the front of the car, you'll have no crumple zone

I'm not talking about a long hood so much as a tall hood relative to the rest of the vehicle - the car starts, then suddenly it's nearly as tall as the roof. Example: here's the concept mode [greengirlsglobal.com] for the Chevy Volt. I took one look at it and smacked my head, anyone who knows aerodynamics can see that that thing is going to have the aerodynamics of a rolling brick (spoiler: that's a whopping 0,43 drag coefficient on a supposedly "efficient" car!). Nobody should have been the least bit surprised when it changed d

Here's a picture [anderbergconsulting.com] of an actual prototype SkyTran car. You're probably right; those first pictures were just early artistic concepts. Here's another [innovativeisrael.dk]. They're building this system now in Tel Aviv.

As for all your stuff about cars, do you have any examples of cars which are decent aerodynamically, and not just infeasible prototypes and concepts?

Well, one of the most extreme examples was the "car" I was on the waiting list for, Aptera's 2e [electric-car-insider.com], which was about 2 months away (I have their old internal corporate schedules and checklists) from shipping to customers when the board brought in Paul Wilbur to manage the company. Wilbur is a Detroit car exec who had ran one company into the ground after the next; the first thing he did after taking over the company was order a redesign nearly the whole vehicle trying to "mainstream it". The changes ruined the

. If you have a highly raked windshield (optimal aerodynamics) then the driver and passenger have to be located a bit further back from the front of the car for headroom reasons, so there's still plenty of room ahead of them to the foremost point on the vehicle.

But the long windshield makes for bad UI. How do you clean the small angle where the dash and windscreen meet? What is the effect at night, since you are looking through more glass and at a more distorting angle? Extending the A-pillar along your raked windshield makes it almost worthless for rollover protection.

Aerodynamics maybe your "favorite" design constraint, but it's far from the only one.

Most of our driving is straight-line interstate. The market here values straight-line performance and a smooth ride. I think that without exception, cars with exceptional handling are niche players in the US market, regardless of national origin. Sometimes the EU market screws up our fun, too. For instance, the original Neon - while crappy in almost every way - did pretty well on the autocross circuit because it was so short and fat. However, in their effort to make it a "world car" suitable for narrow EU s

Be useful in places where there aren't really roads. Bet the things work great in deserts. In my experience though, steering is a problem. You can't really steer a hovercraft easily. The rudder does hardly anything.

Be useful in places where there aren't really roads. Bet the things work great in deserts.

Only on the flat. You can't cross dunes in a hovercraft. Nor, in fact, can you take any significant grade, nor can you cross any obstacles which very closely approach the size of the gap between the ground and the hard bottom of the craft. Not the skirts, but the hull itself.

Although something that runs along water and would somehow work on highways would be an interesting, albeit small niche market and likely not anything that Toyota would care about. I'd love one. A local cruise operator actually has a commercial hovercraft that they had hoped to used as an inter island ferry, except that it wasn't terribly reliable and was a cast iron bitch to tow back to port.

I'm not sure why a person would want a hovercraft for general use. It's way more efficient to just have car that rolls on wheels. Lifting the entire car off the ground with a cushion of air is terribly inefficient. Not that there aren't any uses at all, but as a general purpose vehicle on public roadways, it seems like a terrible idea.

The trouble with those car-sized hovercraft is the turning and braking profile, which is nowhere near good enough for public roads designed for cars. Now a design something like the Aero-X [aerofex.com] hoverbike might be able to improve on that - by hovering a bit higher and tilting the entire craft, you could effectively vector a large proportion of the lift airflow for turning force, as opposed to redirecting a bit of the horizontal thrust only with a fin as with conventional hovercraft. Aerofex don't seem to make any such claims about their design though, they seem to be targeting off-road use only, and I guess turning that way might present problems for other road users/pedestrians getting hit by the airflow.

TFA doesn't claim "hovercraft" That's editorial. What would happen if you found a way to duct air under the tires? Have them lifted 1mm off the ground by a thin layer of air. Part of braking or any other maneuver would be to cut the air, and the tire is then in contact again. The tire still bears 100% of the car weight, but has no contact with the road while under certain cruising conditions.

The "announcement" is overblown from a throw away comment with no detail or follow-up. No official press relea

The problem I see with hovercraft (on the same roads as automobiles) is acceleration. The wheels do a lot more for the car than simply supporting the weight - contact with the road surface is absolutely essential for accelerating forward, braking, turning, and keeping the front of the car pointed in the direction of travel. In a hovercraft, you need some alternate mechanism for that - usually pushing with or against the air (i.e., propellers and fans). How does the performance of those alternate means fo

My presumption is that they're still using wheels for acceleration. For example, in a front-wheel drive car, you could hover the back wheels, at least until you need traction from them (for example, turning). With a pulse and glide configuration, you could even hover the drive wheels for a good chunk of the time.

Oh, and just an additional comment, from my past experience in the auto industry: this wasn't an "oops, I wasn't supposed to say that!" remark. The Japanese companies are in general very good at controlling information flow; this was clearly planned for him to say that. But the reason he said it was almost certainly not to prepare people for the coming day of flying cars; it's about perception. It's a major brand positive for an auto maker to be perceived as high tech / cutting edge / innovative, and they w

Oh, and just an additional comment, from my past experience in the auto industry: this wasn't an "oops, I wasn't supposed to say that!" remark. The Japanese companies are in general very good at controlling information flow; this was clearly planned for him to say that. But the reason he said it was almost certainly not to prepare people for the coming day of flying cars; it's about perception. It's a major brand positive for an auto maker to be perceived as high tech / cutting edge / innovative, and they want to culture that.

Remember Rick Wagoner, the guy whose tenure at GM made a graph of the company's stock look like a double diamond ski slope? Of all of the things that he could have regretted, he's stated that the number one thing he regrets was axing the EV1 (late 90s electric car) program. The EV1 lost tens of thousands of dollars per unit and there weren't many made so there was major overhead on top of it; but by axing the program to save a little money, they willingly gave up the perception of being a tech innovator, right at the time the Japanese companies were introducing hybrids. Even to people who weren't considering buying a Prius or Insight - aka, the vast majority of consumers - the very perception that Toyota and Honda appeared to be high-tech innovators demonstrably influenced consumer buying decisions.

Car makers have slick PR teams who survey and carefully try to manipulate the public perceptions about themselves to influence buyer behavior. Expect that the decision to mention this came straight from one of them.

Yes, but companies kill various programs all the time. Even Toyota [wikipedia.org] and Honda [wikipedia.org] have introduced various electric cars, fuel-cell cars, natural gas cars, etc for lease and axed them just as quickly. Heck, Honda even repo'd the EV Plus and crushed the cars just like the EV1. Usually this happens without incident. The only thing unique about the EV1 is the almost cult-like following that it appeared to generate. This really appeared only after the program was canceled. It would be unreasonable to say that t

The EV1 was indisputably both the most advanced and most popular electric offering at the time, and most critically, they basically gutted all similar research and sold off their patents, not even pursuing hybrids. Their selling off of the patent rights also made it impossible for several other companies to have continued their EVs even if they had wanted to. GM was also the most active and public of companies trying to kill off the ZEV mandate. So all together, it's not surprising that they earned the lio

My "car" already "hovers" a few inches above the road, riding on "tires" that support the weight and provide propulsion. One engineers throw-away comment being blown out of proportion isn't that big of a deal.

call me a fogey but we cant handle flying cars and we certainly cant begin to handle hovering ones either.

Here in america you need look no further than your local road to confirm my assertion. just drive to lunch today and count how many people change lanes without a signal, make an illegal left across two lanes of opposing traffic, run red lights, cut eachother off, and tailgate. We're a fucking mess. On the highways every single vehicle routinely travels 15 miles or more above the speed limit, even though we've had reliable cruise control thats far superior to our own clumsy right foot for more than 3 decades. Drivers are glued to their phones or face down in the texting position for the majority of their commute. We're horrible at looking ahead and predicting when traffic will stop, instead choosing to slam on our brakes and let the other guy do his best to stop. Although every drivers manual reads we should slow down if someone wants to merge into our lane, we instinctually speed up or ignore them. Try an experiment: go the speed limit in the center lane of the highway and see how many furious drivers pound their horns and flash their headlights. Better yet, try driving in the left lane on a road that isnt limited access, a speed limit something around 35mph, and see how many people completely lose their minds despite the fact that what youre doing is entirely legal. And speed? The only time speed factors into any collision in america is when its fatal, and even then its only if the wreckage is catastrophic or the occupant a celebrity. We wrecklessly whip across 3 lanes of traffic and insist on maintaining our lead regardless of how congested the roads are. We categorically ignore speed limits in a construction zone despite a quad-damage boost to any citation received. We race along at all hours of day and in all seasons as if a collision would have no consequences to us, because we're all we think of.

The best innovation in automobiles has been to autonomize them, but compared to things like rail even an autonomous car is laughably inefficient and merely perpetuates a host of systemic and unsustainable problems related to automobiles nonetheleast of which is climate change.

"Try an experiment: go the speed limit in the center lane of the highway and see how many furious drivers pound their horns and flash their headlights"

Yeah , I wonder why that could be. Perhaps because some arrogant ass is blocking the lane when he's supposed to move over if the nearside lane is clear. If you want to play traffic cop go sign up and do the 2 years training, otherwise get out the fecking way.

"Try an experiment: go the speed limit in the center lane of the highway and see how many furious drivers pound their horns and flash their headlights"

Yeah , I wonder why that could be. Perhaps because some arrogant ass is blocking the lane when he's supposed to move over if the nearside lane is clear. If you want to play traffic cop go sign up and do the 2 years training, otherwise get out the fecking way.

Yet those same furious drivers will inevitably pass on the right into dense, slower moving traffic, ride someones tail until that driver gets nervous and speeds up enough to let them pass that center lane car only to further pass into the the left lane which was open in the first place. The moral of the story is, once you hit the highway, someone is always an idiot to someone else whether you are actually driving like an idiot or following the letter of the law.

Again, the speed limit is critical as that is the maximum speed you are supposed to be traveling on american highways, no faster, and as such im considered at cruising speed. on a 3 lane highway, the left lane is for passing, and center lane(s) cruising. When you choose to drive slowly or enter or turn off the road, use the right lane. You. along with countless other drivers are incredible proof that its possible to pass a drivers test administered in the United States with no more than a passing interes

The California law explicitly states "Notwithstanding the prima facie speed limits".

That is true. It is also your duty to allow merging traffic to join the highway where possible. In busy urban areas with lots of on and off ramps, a dense line of cars in the right lane will also impede traffic and threaten safety.

Also, California (and Texas, IIRC) are examples of rare states without "absolute" speed limits, which means if you can justify that your speed was reasonable and safe, even if above the "prima facie" limit, you may be able to get out of a citation. (I don't know if this is st

In Florida, your behavior is a moving violation equivalent to driving on the wrong side of a double-yellow. You may not like it, but you are breaking the law even if everyone else is speeding. Get to the right lane.

No it's not. Just last year [wtsp.com], Florida passed a law which fines people $60 for driving MORE THAN 10 MPH BELOW the speed limit in the LEFT LANE on a highway.

Given that they had to institute a specific law for people driving FAR BELOW the speed limit in the LEFT lane, I sincerely doubt they are going to pull someone over for driving AT the speed limit in the CENTER lane.

(2) Upon all roadways, any vehicle proceeding at less than the normal speed of traffic at the time and place and under the conditions then existing shall be driven in the right-hand lane then available for traffic or as close as practicable to the right-hand curb or edge of the roadway except when overtaking and passing another vehicle proceeding in the same direction or when preparing for a left turn at an intersection or into a private road or

"Try an experiment: go the speed limit in the center lane of the highway and see how many furious drivers pound their horns and flash their headlights"

Yeah , I wonder why that could be. Perhaps because some arrogant ass is blocking the lane when he's supposed to move over if the nearside lane is clear.

Red herring. Where did the GP say that the nearside lane was clear? I've often been overtaking a string of slow-moving traffic, only to have some wanker in a big German saloon (the sort with the aggressive-looking LED running lights designed to intimidate peons without flashing and honking) drop out of hyperdrive 6" behind my tailpipe. If the nearside lane did have room to swing a cat, they would use it to pass you.

5. Upon a roadway which is divided into four or more lanes, a vehicle shall not impede the normal flow of traffic by driving in the left lane; provided, however, this paragraph shall not prohibit driving in a lane other than the right-hand lane when traffic conditions or flow, or both, or road configuration, such as the potential of merging traffic, require the use of lanes other than the right-hand lane to maintain safe traffic conditions. [Emphasis added]

Better yet, try driving in the left lane on a road that isnt limited access, a speed limit something around 35mph, and see how many people completely lose their minds despite the fact that what youre doing is entirely legal.

No, it isn't legal. Look up Impeding Traffic. You aren't allowed to impede the normal flow of traffic, even if that traffic is violating the law.
--JimFive

No, it isn't legal. Look up Impeding Traffic. You aren't allowed to impede the normal flow of traffic, even if that traffic is violating the law.

Impeding Traffic varies from state to state. In Missouri, for example, drivers in the left lane must move faster than drivers in the right line (assuming both lanes are for the same direction); but only up to and including the speed limit. If the driver in the left lane is at the speed limit, and the driver in the right lane is exceeding the speed limit, the right-lane driver is violating the law while the left-lane driver is obeying the law.

The Missouri "Keep right" laws don't support your scenario, though. According to this [mo.gov], all drivers should drive as far to the right as safely possible except if passing or preparing to turn left. If another car is able to pass you on the right, then you are not driving as far right as possible. In your scenario, the person in the left lane is violating the "keep right" law and the person in the right lane is violating the speeding law. Both of your hypothetical drivers are in the wrong.

call me a fogey but we cant handle flying cars and we certainly cant begin to handle hovering ones either.

You might be a fogey, but you're completely correct. I was just driving up the 101 and watching people lane drift and thinking this very thing — people can't handle the cars we have now, they certainly won't be able to handle a vehicle with reduced friction.

Try an experiment: go the speed limit in the center lane of the highway and see how many furious drivers pound their horns and flash their headlights.

How about you keep your butt over in the right lane if you are not passing anybody like the law says? I see that you are one of those douchebags who thinks it's his personal responsibility to make sure nobody is speeding. You seem all to eager to bitch about how bad others drive but maybe you should look a little closer in the mirror. You're kind is a reas

Although every drivers manual reads we should slow down if someone wants to merge into our lane

This is wrong and it drives me nuts. People don't know how to merge. You're are supposed to drive at a consistent speed if someone is trying to merge into your lane. The merger is supposed to adjust their speed. Their supposed to decide whether to slow down or speed up to merge in front or in back of you. If both start slowing down and speeding up it becomes a confusing guessing game. Now if you mean by slowing down providing enough of an opening fo

I doubt that, there would be no friction with the ground meaning it would corner and stop poorly, bridges and other areas with wind gusts would be huge problem. Hover crafts have been around for a while they are notoriously difficult to control.

Reducing Road friction, from someone in the North East means the same as driving on Icy Roads.

Now the people who live in areas where we are use to this sort of driving it may be good. But the South they will just be stuck in traffic for weeks because they just don't know how to drive on reduced friction.

As a start, Toyota should first start with developing a technology to allow the tires to rise above the surface of the pavement just a few millimeters when the road is wet. This would give many of the same performance characteristics that you'd get with a hover car, but it'd be much easier to achieve.

Car tires contacting the ground gives you two huge advantages: The car's motion is (assuming no skidding) restricted to a single axis determined by the direction the front wheels are pointing. And the car's orientation is physically coupled to the road (i.e. it more or less points in the direction it's traveling).

Once you start hovering, you lose these two and direction and orientation are no longer coupled to any part of the car. The car no longer moves forward in the direction the wheels are pointed

In my dream, I had the idea that there was an electromagnetic tape that the bike drove over. The thing worked like a hover bullet train. The tape recycled around the bike like a tank tread. The idea may or may not work because it is very complicated for the maglev trains to work in a static state of the rails. For a bike to cycle tape/film around to produce lift would be yet another feat of engineering. So while it was just a dream, I don't think it is totally theoretically impossible.

That locks us into an impossible scenario - anything related to a hovercraft as we know it is completely unsuitable as a consumer highway vehicle. So, the company MUST be talking about something else entirely.

The 1960 Curtiss Wright Air Car [roadandtrack.com] did this. It's a hovercraft, built to look like a car with bumpers, chrome, two-tone color scheme, and convertible top. Top speed around 38 MPH. 2.5MPG.

Race car design goes in the opposite direction, trying to get as little lift as possible. Some Formula One cars were built with big fans sucking out air from below the vehicle to increase tire contact forces. Worked too well; prohibited by a Formula One rule change.